


Betrayal

by Phoenix_Phyre1749



Category: Gravity Falls
Genre: BillDip, Demon Dipper Pines, Dipper and Mabel are 18, Evil Dipper Pines, Help, Human Bill Cipher, M/M, idk - Freeform, idk what to put here, spoilers????
Language: English
Status: In-Progress
Published: 2020-12-10
Updated: 2021-01-06
Packaged: 2021-03-09 19:19:32
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 5
Words: 4,583
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27991395
Author URL: https://archiveofourown.org/users/Phoenix_Phyre1749/pseuds/Phoenix_Phyre1749
Summary: This was supposed to be a normal summer. Mabel gets her boys, and glitter, and sweets, and I get to sit in the woods and read. But... the journals, the portal... Mabel BETRAYING me. So.... I decided to do the same. I contacted an old enemy, and new ally, and I am going to turn the world into ruins. ;)
Relationships: Bill Cipher/Dipper Pines
Comments: 21
Kudos: 84





	1. The Portal

**Author's Note:**

> Ok so if you did not read the tags, MABEL AND DIPPER ARE 18 IN MY AU. Enjoy the chapter :D

"Grunkle Stan...... I trust you"

Mabel let go of the pole the button was on and let herself float up in front of the portal.

"Mabel, are you crazy!? We're all gonna-"

Before I can finish berating my "sister", the countdown finishes. This is it. The portal is opening and we're all going to day because of my lying uncle and my idiotically naïve sister. There is a flash, then a feeling of weightlessness, and then falling. I hit the ground and rub my forehead. I look up and see a silhouette of a vaguely human man walking through the portal. He walks forward and stoops down to the journal. He puts his hand on the front cover for a moment, then picks it up and puts it in a pouch on the inside of his tattered trench coat. 

"W-what? Grunkle Stan, who IS this guy?" Mabel asks.

"The author of the journals. My twin brother."

I look at Mabel and Soos who have looks of pure utter shock on their faces.

"Finally! After all these long years of waiting and working, you're ACTUALLY here! Brother!"

And then the mystery man clocks him. It takes quite a bit of self control to not laugh at his deserved pain.

"OW! What the fuck was that for?!"

"This was an INSANELY risky move, restarting the portal like this! Are you illiterate, or did you just IGNORE ever fucking warning I put in the journals?!"

We all sit and watch the 30 second fight before Mabel interrupts the two brawling.

"Hi, Mable here, one quick question, what in the world is going on???"

"Stan, you didn't say anything about children! And what appears to be a large hairless gopher."

Ok wow, rude much? I already don't like this guy. He's entitled and walks into a room acting like he's the smartest one there.

"I-I have a niece and nephew? Greetings, "he says, reaching out to shake Mabel's hand. "Do kids still say that?"

While he chats with Mabel, I try to distance myself from these backstabbers and liars. It finally sinks in. Mabel turned her back on me. She decided to trust a known liar, who she's known for less than three god damned months over her own twin brother. How could she? I guess the author was right. Trust no one. I feel this red hot anger burning in me. I want revenge. For her to feel as betrayed as I am. And I know exactly who to call for that. I crack a small, yet sadistic, smile as the thought oh her screaming and crying in betrayal and pain fills my head.

"WHAT!!!"

My head snaps up at the loud noise. I look at the author, who made the noise while talking with Stan.

"Okay. Fuck. It's alright. We should have a while before they find this room. We just have to lay low and think of a plan."

He takes out the journal and a pen and starts scribbling.

Mabel makes the oh-so obvious statement that we're all going to be stuck here for a while and decides to bring up their past. Idiot. Time and place. We are in neither.

But I sit there and listen to their sob stories they called lives. The science fair, Gravity Falls, being a con man. Everything. They are both so stupid in so many different ways. It's a miracle that they're both still alive, with how easily Fordsy here is manipulated and how many illegal activities Stan participates in. I honestly find it tragic that they wasted themselves. Lies, backstabbing, and pride ruin another one of humanities’ chances for greatness. What. A. Waste. They balance each other perfectly. Stan has ambition, social skills, charm, and general street smarts, while Fordsy has intellect, skill, precision, and impulse control. They could have been great together. But noooo, hubris and betrayal ruin it. I can't wait to leave this dingy basement, call Bill, and make the deal. I know he'll take it. I mean, he can't afford not to.

"I heard talking from the floor" an agent yells to his buddies.

Even I panic for a moment. I can't have anyone here going to jail.

"FORD! Here! Make them forget!" I shout.

"Dipper, you're a genius! If I can adjust this to a radio wave frequency.... GOT IT! Everyone, plug your ears!"

We all crouch down and plug our ears. A vibration goes out, and the agents won't remember a thing. So that's one obstacle scratched off. Ford deals with the agents, and I sneak off into the woods with journal 2.


	2. Terms And Conditions

**Summary for the Chapter:**

> Dealing with a demonic Dorito.

**Notes for the Chapter:**

> Ok so this chapter took longer than expected, but I hope you guys like it!

As I get deeper and deeper into the forest, I allow myself more freedom. Hmmmm. What exactly am I going to say? I know my goal, and he probably does too, but still. I finally reached the clearing I had in mind. I set up the circle, and say those precious words.

“Triangulum, Entangulum, Veneforis Dominus ventium! Veneforis venetisarium!”

A triangular hole opened up, with the edges surrounded by blue fire. Bill’s eye appeared, and then the rest of his “body” did too.

“Well, well, well, why in the world would you of all people summon me, Pinetree? Want me to smash another laptop? Possess your body again? OR- are you having…. Hmm, how should I put this…..” he said tapping his non-existent chin.

_**“Family issues?”** _

“Don’t be an ass Bill. You know exactly why you’re here and what I want. Now do you want to make a deal with me, or not?”

“Oh of course I do Pinetree! BUT. I want to hear you say what you want. Besides, for deals to work, we need to be verbal. And you’d have to say it eventually anyway. Now.... what do you want Pinetree?”

I take a shaky breath in. Its harder than I thought to actually say it. But I have to say it to get it.

“I want to make this entire world suffer. I want to turn my back on all of them, like they did to me. I want blood, chaos, and pain. I want to be your number two in taking over this PATHETIC PLANET FULL OF MISERABLE LOWLIFE BACKSTABBERS!” I accidentally screeched.

Bill has a look of almost shock on his… face?

“Okay I am going to be quite transparent here. I am absolutely thrilled that you want to be on my side! And my right hand man at that! However there are some… added necessities at the second bit. If I decide on a right hand man, it’s permanent. I don’t trust easy, so its best to have an immortal be my number two. So, you would have to become immortal, and preferably a demon if you want to be number 2. Are you willing to sacrifice your very humanity for me?”

“Yes. There is nothing good about being human or living amongst them. The more “humanity” I can wash my hands of the better.” I say sternly.

“Fantastic! Now. I know your needs and conditions, time for mine. My takeover isn’t happening until much later this summer. I want you to spy on Sixer, Fez, and Shooting Star for me until then, alright? I’m also going to insist that we have this wonderful little doo dad I call a mind link. It will allow us to communicate mentally without issues, and will allow both of us to see each other's minds and access them.” He says, clearly unable to contain his joy.

“I agree to both of those. With the mind link, I’ll be able to trust you a lot more, and the spying thing is no issue for me.” I say happily.

“Amazing! So, if there are no more conditions on either side”, He sticks his hand out to me, encasing it in magical blue flames.

**_“Do we have ourselves a deal, Pinetree?”_ **

I grab his hand and shake it.

“Yes we do Bill.”

As soon as we let go, I crack a huge, sadistic, smile. We are going to have quite a bit of fun now, aren’t we?

“Alright let’s get the mind link set up. Just give me one moment…”

He draws a glowing circle above my head, putting an equilateral triangle in the center, and closing his eye.

“Ponte gap, coniungant animos.”

As soon as he finishes saying the spell, I can feel his mind. It's like a ghost in my own head.

_Bill?_

Bill heartily chuckles.

“I see you’ve already figured out the communication part of the link! My you’re quite smart. I can’t wait to make you even smarter!”

“What exactly do you mean by that, Bill?”

“Well, try and figure out. Use the mind link, Pinetree!”

“Alright then.”

I close my eyes and try to focus my mind. Bill’s mind is now permanently connected to mine, so I just have to find his mind. I try to visualize a bridge connecting our minds together. Once I can see the bridge in my mind’s eye, I imagine myself crossing it.

_There we go, Pinetree! I want to teach you magic as soon as I can!_

“Really!? I would love learning magic from a master like you, Bill!”

“Fantastic! I’ll prepare the spell to turn you into a demon, but it won’t be ready till about two in the morning tomorrow.”

“Alright, I’ll meet you here around that time tomorrow, ok?”

“Definitely! Now, you should get back to the shack before they start getting worried. I’ll be in your mind if you need me, Pinetree!”

“Later, Bill!” I say, waving at him as I walk away.

My mind is racing at the speed of light as I walk back to the shack. The deal went so much better than I could have ever hoped! Bill actually wants me as his right hand man! We are going to destroy this pathetic world, and I get vengeance on any idiot who has ever wronged me. This is going to be so much fun.

_Yes it is, isn’t it?_

_Bill! Were you listening to all of that?!_

_Kinda. Your thoughts were so damn loud, it was more like you were yelling them into my head. You really want this, don’t you?_

_Absolutely._

_Good. Humans have wronged you. It was an idiotic idea on their part. You are smart, and creative, and more determined to get what you want than any human I’ve ever interacted with._

_R-really?_

_Not used to people giving you the praise you deserve, eh? Well get used to it. You are an amazing person and anyone who thinks otherwise is a liar, an idiot, or both._

_...Thanks, Bill. I really appreciate that. No one ever takes me seriously or genuinely likes me._

_I know. And its idiotic. But I like you, and every single one of my friends will too. We’re all freaks, You will be adored, and accepted._

_Do you promise?_

_I promise, Pinetree._

Almost as soon as he finishes that last sentence, I see the shack. As soon as I get close to the front door, Ma-Shooting Star runs out and hugs me.

“Bro-bro, why did you run off? I was so worried about you! You’ve wanted to meet the author of the journals almost all summer, why did you run off when he got here?”

“Sorry Mabel, I just got kinda overwhelmed. I just wanted to clear my head. Sorry for not telling you.”

“Its a-okay bro-bro!”

Fez shoos us upstairs so he can talk with Sixer.

“Mabel? I’m gonna go to bed, ok?”

“Oh… okay bro-bro. You must be exhausted after the day we’ve had. Goodnight Dipper!”

“Night Mabel.”

The last thing I hear before I go to sleep is Bill.

_Good night Pinetree. Sweet Dreams!_

**Notes for the Chapter:**

> See you next chapter!


	3. Trust

**Summary for the Chapter:**

> Dipper starts working to gain Ford's trust, as well as bonding with Bill.

**Notes for the Chapter:**

> This is my longest chapter yet!

_Pinetree~_

_Yes, Bill?_

_Good morning!_

_Morning Bill!_

_I need you to try your best to get Sixer to trust you. He has secrets and information that is invaluable to us and our take over. Can you start that now, or do you want to wait until you are a demon?_

_I can start now. Seems simple enough, I mean, all it is is emotional manipulation and lying right? I can do those fairly easily._

_Fantastic! By the way… I have a little surprise to show you when you get to the clearing later!_

_I swear to gods, Bill, if it deer teeth or something weird like that…._

_No, no! Nothing like that. Just something I think you will like!_

_Alright then._

“DIPPER! BREAKFAST!” Mabel yelled from downstairs.

“Coming!” I yelled back.

_Later, Bill!_

_See ya, Pinetree~_

I run down the stairs, not even bothering to get dressed. When I get to the kitchen, I see Fez flipping a few “stan-cakes” and putting them on one of the bigger plates we have. Sixer and Shooting Star are sitting at the table chatting away about something random. I think this is a good chance to try and endear him to me.

“Grunkle Ford?” I call to get his attention while sitting down.

“Oh! Yes, Dipper?”

“I just wanted to apologize for my behavior yesterday. It was quite rude of me to run off without saying anything.” I say shyly.

“Oh, its perfectly fine Dipper. We were all very overwhelmed yesterday, and I don’t blame you for taking time to collect your thoughts by yourself. I would have done the same thing if I were in your position.” He said with a hearty chuckle.

“Oh that’s a relief!” I sigh.

Fez walks over to the table, setting down the plate of stan-cakes and a bottle of syrup. He sits down and serves himself a few stan-cakes silently.

“Sooo…. Mabel here tells me you’re a fan of my work?” He questions while serving himself.

“Yes! I’ve read journal three front to back several times, added my own entries, and even discovered the hidden messages!” I say, feigning excitement while getting myself some breakfast too.

“My, that’s impressive! You even finding that one is outstanding on its own, but adding your own discoveries and finding my hidden notes? It looks like we have another overachiever in the family, right Stanley?” he says, elbowing his twin.

“Yeah, I guess…” Fez grumbles in response.

For the rest of breakfast, we eat in mostly silence, with occasional attempts at small talk from Shooting Star. As soon as I finish, I excuse myself to go get dressed. I search through my closet for some less dorky clothes. But, all of them are trash. Damn Shooting Star, getting all the good clothes….

_I can help with that, Pinetree._

_Really!? You can give me the style of clothes I’ve always wanted?_

_Of course! Please close your closet door._

_Got it!_

_I close the door and go over to my bed to sit down._

_You know all my favorite bands, right Bill?_

_Of course. You’ve interested me since I met you. And I tend to obsess over things that genuinely interest me._

_Oh~ So you’re saying that you’re obsessed with me? Bill, I’m flattered!_

_I- um…. Shit._

_No, I’m not kidding that’s adorable. And I do the exact same thing._

_Oh…… I-... just get dressed, okay, Pinetree?_

_Okay, okay, I’ll drop it._

I get up and walk over to my closet and throw open the door. Even though I knew it was coming, I can’t help but gasp at my new and improved wardrobe. Band T-shirts, ripped jeans, leather jackets, combat boots, and my signature pine tree baseball cap has been replaced with a black beanie with a dark blue embroidered pine tree on the front. I grab the beanie and hug it to my chest.

_Thank you so much, Bill. They are so amazing. I love them!_

_I’m glad you do, Pinetree! But check inside the bottom drawer~_

_Why? That’s just a jewelry-.... Oh…._

_Go look, Pinetree._

I kneel down and open the bottom drawer. I see an array of earrings, chokers, bracelets, and in the very center, a golden triangle on a black leather band.

_Oh my gods, Bill! You’ve out done yourself! Thank you so much!_

_I’m glad you like them, Pinetree!_

_I very much so do, Bill!_

_You should probably get dressed now though. You’ve been up here for a little while._

_Crap, you’re right!_

I grab a random band shirt, a pair of ripped up black skinny jeans, some Doc Martens, the triangle necklace, and the beanie. I quickly get dressed, brush my teeth, and shove the beanie over my fluffy brown hair. I take a few minutes to check myself out in the bathroom mirror, turning and adjusting my angle as necessary.

“Something is missing….”

_Check the side drawer, Sapling._

_Oh, okay then!_

I open the side drawer to find a few different kinds of black lipstick, and some red lipstick, and both black and white eyeliner. Now I don’t wear it out in public, I maybe kinda stole some of Shooting Star’s make up a few years ago and learned how to do it.

I grab the matte black lipstick and the black eyeliner, and quickly apply them. I check myself out again, and I must say, I look GOOD. I’m radiating confidence, and I look like myself.

_Thank you so, so much Bill!_

_You’re most welcome, Pinetree. Now go win Sixer over. It’ll be hard, but you can do it!_

_Got it!_

I run down the stairs two at a time out of pure excitement. I can’t fucking wait to get Sixer to tell me all his little secrets!

“Hey bro- OH MY GOD WHAT DID YOU DO?!” she screeches

“What do you mean, Mabel? Is something wrong with my outfit?” I ask innocently.

“N-no! Sorry for yelling, you just caught me off guard. You look….nice.”

“Thank you.”

Fucking Shooting Star. Can’t handle people making their own fucking decisions? Gods, she is so selfish, and greedy.

I go over to the vending machine and put in the code to get access to the basement where Sixer probably is. I walk down the dark stairs and get to his lab, where surprise surprise, he’s sitting there with his face shoved in a book.

“Grunkle Ford?” I call out to get his attention.

“Oh! Hello there, Dipper! How can I help you?” he answered.

“I was actually wondering how I could help YOU” I say sheepishly.

“You said earlier that the discoveries I made were outstanding, and I thought you might like an assistant slash apprentice for your research!” I say, excitement in my voice.

“Ah, I see. I didn’t think a young person like you would want to spend large amounts of his free time working with an old coot like me, but I guess I made the wrong assumptions, huh?”

“Why would I care that you’re older, Grunkle Ford? Old just means experienced and knowledgeable. I could learn so much from you! That is if you want to teach me…”

This is going perfectly! Get him to teach me what he knows, then use his own knowledge to destroy him. Easy. As. Pie.

“Dipper I would love to teach you! You’re a smart lad, and you could be of great use to me. So consider your offer accepted.”

“Fantastic! What do you need help with, Grunkle Ford?”

“Well, for now, I would like some assistance in cleaning up the mess the portal left behind. There are hunks of metal and other heavy things I need help lifting.”

“Of course I can help with that!”

We both start cleaning up the remnants of the portal and exchanging random information we’ve learned. Its a true shame he’s lying to me about what he wants. He’s trying to take advantage of the fact that I used to idolize him for free labor and to claim my work.

_It is a shame._

_I know, right? He has such a large ego, he can’t even tell he’s being played like a fiddle. He is a fool._

_He truly is. But the spell is almost ready! Soon you will have the power you need my Sapling!_

_Good._

“Dipper? It’s almost three, we should stop for the day.” Sixer interrupts.

“Oh, already three? I guess you’re right. We can finish tomorrow. Goodnight, Grunkle Ford!”

“Goodnight, Dipper.”

Finally. That old asshole was starting to get on my nerves.

_I know, Pinetree. At least he likes you. That is very good for us._

_It is._

I spend the rest of the day talking with Bill, reading, and drawing. Mabel also came to talk to me, but she didn’t really want to be there. She was just trying to make sure I wasn’t angry with her.

Finally, it’s about one-thirty in the morning. I’m just sitting at my desk waiting for Bill to give me the okay to head to our clearing.

_Pinetree? The spell is almost ready!_

_I’m on my way, Bill._

_Good._

**Notes for the Chapter:**

> See you next chapter!


	4. Dancing with Demons

As soon as Bill gives me the all clear to head to our clearing, I grab my flashlight and sneak out through my window.

As I’m clambering to get off the roof, without breaking any bones, my mind starts to race. This is real. I’m not going to be human anymore in half an hour. I’m going to be a demon, just like Bill, and I’ll get to take over this pathetic world with him.

_ I’m glad you’re so excited, Pinetree. _

_ Was I scream thinking again? _

_ Yep. But don’t worry! I find it really cute. You’re so passionate about this, and I love that. _

I smile and blush at that last statement. He thinks I’m cute! He’s so sweet.

_ Glad you think so my Sapling! But don’t forget about your other surprise~ _

_ RIght! I did forget you had something else for me. _

I enter the forest and head north east to our clearing.

What’s kinda weird, but also really good, is that normally I would be worried about going into the woods this late on my own, but now…. I know I’m going straight into the arms of my demon.

_ Your demon? I like that. _

I can’t even respond out of pure embarrassment. I called him my demon. And he likes it!

_ I am your demon, and you are my sapling. Never forget that, okay? _

_ …..Do you promise? I am yours, and you are mine? _

_ Forever my Pinetree. _

I feel my face heat up and I break into a huge smile. He is my demon, and I am his pinetree.

I finally break into the clearing to find that it is…. not a clearing? Instead of a large circle of grass and flowers, there is a cozy yet spooky looking cabin in the center. There is cloudy smoke billowing out of the chimney, indicating that someone is inside. Bill  **did** say to come back here, so I assume its him inside.

I walk up to the cabin door and knock on the dark oak slab.

“Come on in, Pinetree!” Bill calls out from inside.

I open the door, walking in and closing the door behind me. I turn off my flashlight and set it on a table by the door. 

“Bill? Where are you?” I call out.

“Upstairs, Sapling!” he responds.

I immediately start running up the stairs two at a time. I’m so excited to see him!

“Bill, which room are you in?”

“Eighth door on the left, Pinetree!”

I run as fast as I can to the eighth door on the left and throw it open. But instead of a golden triangle with a top hat and one eye, I see a tall man standing there, back to me. He has blond hair that’s tipped blue, with half of it shaved and dyed black.

“Bill? Is that you?”

The man turns around and smiles at me. Then I hear an unmistakable voice.

“Ding, ding, ding, Pinetree! Sooo… whaddya think of my human form?” he asks hopefully.

Blood rushes to my cheeks and turns them red. I look him up and down a few times. He has tanned skin, and a muscular body. He’s wearing an eyepatch over his left eye, and his right eye is a beautifully violent shade of cyan.

“You look amazing,” I whisper.

He walks over to me, gently grabs my chin and tilts my face up at him.

“Glad you think so, my Pinetree” 

I tear my eyes away from Bill to look at the large spell circle on the floor, with…. a piano in the corner of the room?

“Bill, why the hell is there a piano in here?”

“For the spell my dear. The easiest and most painless way to become a demon, is to dance with one. The more powerful the demon you dance with is, the stronger you will be. Luckily for you, you’re dancing with The King of Demons!”

“That’s amazing, Bill! But if you’re my dance partner, shouldn’t my clothes match yours?” I say gesturing to his outfit.

Its an amazing tuxedo, the coat is black with golden accents, and the tails reach the back of his knees. He’s wearing matching pants, and some black boots with golden buttons, and on his hands he has fingerless black leather gloves. The only thing matching about our outfits is the gloves. I mean, the only change I made to my outfit from earlier today was adding a dark blue hoodie!

“You’re right, Pinetree!” 

He snaps his fingers, and his signature blue fire envelopes me. When the fire dies down, I’m wearing a suit very similar to his. The main difference is instead of golden accents on the boots and jacket, I have silver buttons on both, and every other accent is dark blue. 

“So whaddya think, Pinetree? Does it fit right?”

“Yeah! It looks great, and fits just right. I love it, Bill, thank you.”

“Glad you like it, Sapling. Now!” 

He snaps his fingers and the piano starts playing an eerie, yet beautiful tune.

He extends his hand so that I can grab it.

“May I have this dance?” he asks with a sly smirk.

“Of course my demon,” I say with a smile to match his.

I take his hand and let him lead me to the edge of the spell circle. He puts one hand on my waist, the other raising our joined hands up. I put my other hand on his shoulder, and smile at him.

“Last chance to back out, Pinetree.”

“Never.”

With my final mark of consent, he activates the spell, and the piano music grows louder. He takes the lead, and we start to waltz. 

We swirl around the circle, and a small fire catches at the edge where we started dancing. As we pass runes in the circle, they glow, ignite, and erupt into magnificent cyan flames. We swirl, and circle to the time of the music, slowly being surrounded by fire.

As we start to approach the large rune in the center of the spell, it gets really hot. Bill picks me up, spins us one last time, and sets me on the center rune.

And then my body is engulfed by cyan fire.


	5. Author's Note (Will be deleted)

I am so sorry that Chapter 5 is taking so long! I've been taking a short mental health break, and focusing on my friends and family because of the holidays. It really doesn't hep that I cranked out almost 5000 words in like five days......  
Anyway! I am working on the next chapter as fast as I can, and I'm gonna try and make sure it's extra long because of the wait. In the meantime, feel free to request BillDip oneshots in the comments! 

Thank you for your patience,  
-Phoenix

**Author's Note:**

> Please please PLEASE tell me if I misspelled a name or word, any grammar or punctuation errors I made, and if you want to, leave constructive criticism! I'm trying to get better at writing, and feedback really helps out!


End file.
